Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

A robotic system comprising a mobile robot including a body housing a
rechargeable power source and first electrical contact means disposed on
the body and a docking station including second electrical contact means,
wherein the mobile robot is dockable on the docking station in order to
charge the rechargeable power source. The first electrical contact means
includes at least one electrical contact aligned on a first contact axis
and the second electrical contact means includes at least one elongate
contact, wherein when the robot is docked on the docking station such
that electrical contact is established between the first electrical
contact means and the electrical contact means. The at least one elongate
contact extends in a direction that is transverse to the first contact
axis which permits electrical contact to be established between the robot
and the docking station whilst accommodating a degree of lateral and
angular misalignment therebetween.

Claims:

1. A robotic system comprising: a mobile robot including a body housing a
rechargeable power source and a first electrical contact part disposed on
the body; a docking station including a second electrical contact part,
wherein the mobile robot is dockable on the docking station in order to
charge the rechargeable power source; wherein the first electrical
contact part includes at least one electrical contact aligned on a first
contact axis; and wherein the second electrical contact part includes at
least one elongate contact; and wherein when the robot is docked on the
docking station such that electrical contact is established between the
first electrical contact part and the second electrical contact part, the
at least one elongate contact extends in a direction that is transverse
to the first contact axis.

2. The robotic system of claim 1, wherein the docking station includes a
rear edge and wherein the at least one elongate contact extends in a
direction that is aligned with the rear edge.

3. The robotic system of claim 1, wherein the electrical contacts
associated with the docking station are resiliently mounted in the
docking station.

4. The robotic system of claim 3, wherein the electrical contacts
associated with the docking station are resiliently mounted in a base
portion of the docking station so as to protrude at least partially
therefrom in order to make a positive connection to the first and second
energy receiving contacts of the robot.

5. The robotic system of claim 1, wherein the docking station includes an
activation mechanism to control the second electrical contact part.

6. (canceled)

7. (canceled)

8. (canceled)

9. (canceled)

10. The robotic system of claim 1, wherein the at least one elongate
contact is linear.

11. The robotic system of claim 1, wherein the at least one elongate
contact is at least partly curved.

12. The robotic system of claim 1, wherein the docking station includes
first and second electrical power input sockets.

13. The robotic system of claim 1, wherein the docking station includes a
further electrical contact.

14. The robotic system of claim 1, wherein the pair of electrical power
input sockets are provided on opposed sides of the docking station.

15. The robotic system of claim 1, wherein the first electrical contact
part provided on the mobile robot includes a second electrical contact
aligned with the first electrical contact along the first axis.

16. The robotic system of claim 1, wherein the first electrical contact
part provided on the mobile robot includes a second electrical contact
laterally offset from the first electric contact with respect to a
longitudinal axis of the mobile robot.

17. A docking station for a mobile robot, the docking station including a
base portion providing a platform onto which a mobile robot docks,
wherein the base portion is provided with an electrical contact that is
elongate in form.

18. The docking station of claim 17, wherein the elongate contact is
linear in form.

19. The docking station of claim 17, wherein the elongate contact is
curved.

20. The docking station of claim 17, wherein the base portion is provided
with a further electrical contact.

21. The docking station of claim 20, wherein the further electrical
contact is linear in form.

22. The docking station of claim 20, wherein the further electrical
contact is curved.

23. The docking station of claim 20, wherein the further electrical
contact is parallel to the first electrical contact, and is either linear
in form or curved.

24. The docking station of claim 17, wherein the at least one electrical
contact is resiliently biased.

25. (canceled)

26. (canceled)

Description:

REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of United Kingdom Application No.
1301109.3, filed Jan. 22, 2013, the entire contents of which are
incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The invention relates to a docking station with which a mobile
robot may cooperate in order to achieve certain functions, for example to
replenish a rechargeable power source of the mobile robot. The invention
also relates to a robotic system including a mobile robot and an
associated docking station.

BACKGROUND OF THE INVENTION

[0003] It is becoming commonplace for mobile robots to be used around the
home. For example, there are mobile robots that are designed specifically
for vacuum cleaning and also ones which are designed for floor mopping.
Also, mobile robots may be used in the home as mobile sentries. Such
mobile sentries are equipped with suitable sensor suites to enable them
to navigate a household, or office space, autonomously and detect
abnormal conditions such as elevated heat levels or intruders into the
area.

[0004] Common to such mobile robots is the requirement for them to move
autonomously and so they are typically equipped with a rechargeable power
source in the form of a battery pack in order to decouple the robot from
dependence on wall-mounted power sockets. Typically the robot will be
configured with an internal power monitoring routine so that it has a
level of self-awareness relating to the level of electrical power that
remains. When power levels are low, the robot is able to make its way
back to a docking station with which the robot can connect in order to
replenish its battery pack.

[0005] Mobile robot docking stations principally are provided with an
electrical charging system having a set of contacts. The contacts are
engageable with complementary contacts on the robot in order to provide
an electrical charging current to the robot. However, docking stations
may also have the facility to provide radio signals or other emissions in
order to assist the robot in locating the docking station. Still further,
in some robotic vacuum cleaner applications, the docking stations are
equipped with dust extracting devices which are able to empty the dust
bin of the mobile robot when it becomes full, thereby removing this
frequent task from the user so as to increase the autonomy of the robot.

[0006] However, with such complexity come drawbacks. Often, mobile docking
stations are large bulky items which need to be placed close to a power
socket in a room of a home. Their physical presence has a significant
visual impact and this detracts from the overriding principle of mobile
robots that they should minimize impact on the user.

[0007] It is with these issues in mind that the invention has been
devised.

SUMMARY OF THE INVENTION

[0008] In a first aspect the invention provides a docking station for a
mobile robot, the docking station comprising a base portion that is
locatable on a floor surface and a rear portion that is pivotable with
respect to the base portion. The docking station is therefore portable
and low profile which helps it be unobtrusive in an environment in which
it is used. This is particularly important in a domestic dwelling for
example where minimum clutter is usually desired. Also, the hinging
action enables the docking station to be folded away into a compact
stowed configuration if desired.

[0009] In order to provide an element of `feel` to the user when folding
and unfolding the docking station, a pivotable interface between the base
portion and the rear portion may include a detent formation that
releasably holds the rear portion in the upright position with respect to
the base portion. Thus, the docking station is held in a deployed
condition until a user asserts a predetermined force in order to perform
a folding action.

[0010] Although in theory the rear portion could be pivotably mounted to
the base portion in a variety of manners, in one embodiment the rear
portion is snap-fitted to the pivot region of the base portion.
Preferably, the pivot region includes pivot axles onto which sleeve
members of the rear portion may be received so as to be able to slide
relative to the pivot axles.

[0011] The base portion may include charging contact means for
establishing an electrical connection to a mobile robot when it is docked
on the docking station. The contact means may comprises first and second
contacts adjacent to one another and they may be elongate in form which
accommodates a range of lateral and angular misalignment between the
robot and the docking station.

[0012] Although the power to the contacts means may be provided
constantly, as a safety mechanism the docking station may include an
activating mechanism that is triggered by the robot as it moves into a
correct docking position. Although this may take the form of an
electrical interlock involving a handshake protocol between the robot and
the docking station through the contact means, in one embodiment the
activating mechanism is mechanically actuated as takes the form of a
movable lever that is pivoted about the base portion of the docking
station. In a preferred embodiment the lever is pivoted about a rear
portion of the base station and so is therefore able to move in
cooperation with the folding action of the docking station.

[0013] The docking station may be placed against a wall of a room and in
close enough proximity to an electrical mains power outlet to be coupled
to it via a cable. In order to provide a user with flexibility in
locating the docking station, in a further aspect the invention provides
a docking station for a mobile robot, including a first side portion and
a second side portion and housing an electrical system having power input
means, wherein the power input means includes a first power input socket
provided on the first side portion and a second power input socket
provided on the second side portion.

[0014] In being able to choose to connect a power supply plug/jack to
either side of the docking station, the user is providing with more
flexibility about where they can locate the docking station. Although the
side portions may be any face of the docking station, in one embodiment
the first and second side portions are located on opposite sides of the
docking station and, preferably, are located on a rearmost edge of the
docking station which is locatable against a wall, in use.

[0015] Since there are at least two sockets, to guard against adverse
affects of connecting a plug to each socket simultaneously, each socket
may contain a switch that disables the other socket once a plug has been
inserted.

[0016] The sockets are in electrical communication with a control module
housed within the docking station which controls the flow of energy to
electrical contact means of the docking station. In order for the mobile
robot to receive power from the contact means, it is required to
manoeuvre itself into a suitable position on the docking station. The
ability of a mobile robot to manoeuvre itself into an acceptable position
depends to a large extent on the effectiveness of its navigation system.
In order to ensure that the mobile robot is robust in its ability to dock
correctly with the docking stations, means are desirable to allow a
degree of misalignment, both laterally and angularly, between the docking
station and the mobile robot yet still achieve a successful docking such
that the mobile robot is able to receive charging energy from the docking
station. Therefore, in a further aspect, the invention provides a robotic
system comprising a mobile robot including a body housing a rechargeable
power source and first electrical contact means disposed on an underside
of the body and a docking station including second electrical contact
means, wherein the mobile robot is dockable on the docking station in
order to charge the rechargeable power source. The first electrical
contact means includes at least one electrical contact aligned on a first
contact axis and the second electrical contact means includes at least
one elongate contact, wherein when the robot is docked on the docking
station such that electrical contact is established between the first
electrical contact means and the electrical contact means, the at least
one elongate contact extends in a direction that is transverse to the
first contact axis.

[0017] Since the at least one electrical contact on the docking station is
transverse to the at least one electrical contact on the robot, the
system accommodates both lateral and angular misalignment between the
mobile robot and the docking station.

[0018] To help the electrical contacts on the mobile robot to engage
reliably with the electrical contacts on the docking station, the
electrical contacts on the docking station may be resiliently mounted in
the docking station, preferably mounted in the a base portion of the
docking station so as to protrude at least partially from it.

[0019] The flow of electrical energy to the docking station contacts may
be regulated by an activating mechanism that is movable by the robot as
it adopts a docked position. The activating mechanism thereby serves as a
safety feature to guard against a user inadvertently touching energised
contacts.

[0020] The activating mechanism could take the form of an electrical
interlock between the contacts of the docking station and the mobile
robot, or a mechanical interlock. In one embodiment, the activating
mechanism is a mechanical interlock and is in the form of a hinged lever
that is optionally pivotably mounted to a rear portion of the docking
station.

[0021] In a further aspect, the invention provides a docking station for
providing a charging service to a mobile robot by providing a platform
onto which the mobile robot may dock wherein the base portion is provided
with an electrical contact that is elongate in form. In one embodiment a
pair of elongate contacts are provided and these are linear in form. In
one embodiment the elongate contacts are formed from nickel coated brass
and are approximately 60 mm in length and approximately 5 mm wide. In
essence the contacts must be longer than they are wide and the precise
dimensions will be determined largely by the dimensions of the base
portion on which the contacts are installed.

[0022] In an alternative embodiment the elongate contacts may be arcuate
and may be dissimilar in length.

[0023] It should be appreciated that preferred and/or optional features of
either of the abovementioned aspects of the invention may be combined
with any of the other aspects of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order that the invention may be more readily understood,
embodiments will now be described by way of example only with reference
to the accompanying drawings, in which:

[0025] FIG. 1 is a perspective view of a room in which is located an
exemplary robotic system comprising a mobile robot and a docking station
in accordance with the invention;

[0026] FIG. 2 is a schematic view of the mobile robot, from underneath,
illustrating the layout of its components;

[0027] FIG. 3 is a system diagram of the electronic control system of the
mobile robot;

[0028] FIG. 4 is a perspective view of the docking station shown in FIG.
1--here the docking station is in a deployed condition;

[0029] FIG. 5 is a perspective view of the docking station in a folded or
`stowed` condition;

[0030] FIG. 6 is a perspective view of the back portion of the docking
station separated from the base portion of the docking station;

[0031] FIG. 7 is a perspective view of the base portion of the docking
station in a partially disassembled condition that illustrates the
pivoting mechanism provided on the base portion;

[0032] FIG. 8a is a view of the docking station in FIG. 5 from underneath
such that the docking station is in a stowed condition; FIG. 8b is a
section along the line ZZ-ZZ in FIG. 8a and FIG. 8c is a section along
the line Z-Z in FIG. 8a;

[0033] FIG. 9a is a view of the docking station in FIG. 4 from underneath
such that the docking station is in a deployed condition; FIG. 9b is a
section along the line XX-XX in FIG. 9a and FIG. 9c is a section along
the line X-X in FIG. 9a;

[0034] FIG. 10 is a partially exploded view of the docking station
illustrating its electrical system;

[0035] FIGS. 11a and 11b are views of the docking station which illustrate
the position of the actuating mechanism in a `power off` position;

[0036] FIGS. 12a and 12b are views corresponding to FIGS. 11a and 11b but
which show the actuating mechanism in a `power on` position;

[0037] FIG. 13 is a schematic view of the robot overlaid on the docking
station in a `nominal` docking position, and FIG. 14 shows a
corresponding partial side view of the robot in simplified form which
shows the electrical contacts of the robot and the docking station;

[0038] FIGS. 15a and 15b are schematic views like that in FIG. 13 but
which show the robot in extreme lateral docking positions on the docking
station;

[0039] FIGS. 16a and 16b are schematic views like that in FIG. 13 but
which show the robot in extreme angular docking positions on the docking
station; and

[0040] FIGS. 17a-c are schematic views similar to that in FIG. 13 which
show alternative configurations of contact means on the docking station.

DETAILED DESCRIPTION OF THE INVENTION

[0041] With reference to FIG. 1 a robotic system 2 includes a mobile robot
4 and an associated docking station 6. In this embodiment, the mobile
robot 4 is shown in the context of a vacuum cleaning robot although it
should be appreciated that this is not essential to the invention and
that the invention is applicable to any mobile robot, in a domestic
setting or otherwise. The mobile robot 4 is autonomous and includes
sufficient processing and sensing capability that enables the robot to
navigate around the room, with the aid of a suitable on board navigation
system, cleaning the floor as it goes.

[0042] The mobile robot 4 is powered by an rechargeable power source in
the form of an internal battery pack (not shown in FIG. 1). Such a
battery pack is generally known in the art and may be composed of a
plurality of cells of a variety of cell chemistries. Cell chemistries in
the lithium-ion family are currently preferred due to their high power
density, low charge loss and lack of memory effect, although other cell
chemistries such as nickel metal hydride and nickel cadmium are also
acceptable.

[0043] The robot 4 is dockable with the docking station 6 so that it is
able to recharge its battery pack when the battery pack nears a depleted
state. The precise way in which the robot is able to locate the docking
station and dock with it does not form part of the invention and so will
not be described in further detail here.

[0044] The docking station 6 is shown in FIG. 1 positioned against a wall
of the room. The docking station 6 includes electrical contact means 8 by
which means the docking station 6 is able to offer charging energy to the
robot 4 once it is in a docked position, as will be described. The
docking station 6 is attached to a mains electrical wall outlet 10 via a
power supply 12 and cable 14 and, in this way, a source of power is
provided to the electrical contact means 8 of the docking station 6.

[0045] The robot 4 will now be described in more detail with reference
also to FIGS. 2 and 3. In this embodiment, the robot 4 includes a main
body 16 which is substantially cylindrical in form and has a height in
the region of approximately 15 to 20 centimetres so that the robot 4 can
move under low objects; chairs and tables for example. In order for the
robot to move on a surface, the robot 4 includes a traction means 20. In
this embodiment, the traction means 20 is in the form of a pair of
wheels, although other solutions such as tracks or legs are feasible. The
wheels 20 are located on opposite sides of the main body 16 and are
operable independently to enable to robot 4 to be driven in forward and
reverse directions, to follow a curved path towards the left or right, or
to turn on the spot in either direction depending on the speed and
rotation direction of the wheels. Such an arrangement is common in mobile
robot applications and so it will not be described in further detail
here. However, it should be appreciated that the specific shape of the
main body 16 is exemplary and, accordingly, the skilled person would
understand that the main body 16 could take on other forms.

[0046] In order to clean the floor surface the robot also includes a brush
bar 22 that is housed in a brush bar housing 24. The brush bar 22 extends
across the body 16 of the robot 4 laterally and is operable to rotate in
order to agitate dirt from the adjacent surface. Although not shown in
FIGS. 1 and 2, it should be appreciated that the robot 4 also includes a
suitable vacuum generator in the form of a motor and fan unit and a dirt
bin into which dirt that is lifted from the floor is collected. The
precise configuration of these components is not essential to the
inventive concept so further detail is omitted.

[0047] The underside of the main body 16 also includes electrical contact
means 26. In the embodiment shown, the electrical contact means 26
comprises first and second electrical contacts 28, 30 that are supported
on the underside of the robot body 16. Each of the first and second
contacts 28, 30 are mounted in an aligned configuration. Specifically,
each contact 28, 30 is aligned with a longitudinal axis L of the robot 4
and are spaced along the axis. The contacts are operable to connect to
the electrical contact means 8 on the docking station 6, as will be
described. Although not shown in the diagram, the electrical contacts 28,
30 are connected to the electrical system of the robot 4 so that
electrical energy provided at the contacts is supplied to the rechargable
battery pack of the robot 4.

[0048] FIG. 3 shows schematically a control system 32 of the robot 4 and
its interfaces with the components described above. The control system 32
includes a controller 40 having appropriate control circuitry and
processing functionality to process signals received from its various
sensors and to drive the robot 4 in a suitable manner. The controller 40
is interfaced into a sensor suite 34 of the robot 4 by which means the
robot 4 gathers information about its environment in order to map its
environment and perform a cleaning route. The sensor suite 34 is also
shown generally in FIG. 1 and includes a navigational sensor 42 for
providing the robot 4 with a panoramic view of its surroundings, and also
a near-field proximity sensing suite 44 to provide the robot 4 with the
capability to detect obstacles. Finally, a bump detecting system 45 is
provided although this is not illustrated in FIG. 1. It should be noted
that navigation sensors, proximity sensors and bump detecting sensors are
common components on mobile robots, particularly domestic robots.
Therefore, the existence of such sensors on the robot 4 is provided here
for completeness but they are not intended to form part of the invention.

[0049] A user interface 46 is provided in order for a user to command the
robot 4 to start/stop a cleaning process, for example. The user interface
46 is also shown generally in FIG. 1.

[0050] The user interface 46 may take various forms, such as one or more
mechanical buttons or even a graphical user interface with touch screen
technology.

[0051] The controller 40 is also configured to supply drive signals to
traction motors 48 associated with the wheels and also to receive
odometry data from the wheels. For this purpose suitable rotational
sensing means 50 such as rotary encoders are provided on the traction
motors 48.

[0052] Suitable power and control inputs are provided to suction motor 52
and brush bar motor 54. Finally, a power input is provided to the
controller 40 from battery pack 56 and a charging interface 58 is
provided by which means the controller 40 can carry out charging of the
battery pack 56 when the battery supply voltage has dropped below a
suitable threshold. It should be appreciated that the charging interface
58 is embodied by the electrical charging contacts 28, 30 provided on the
underside of the robot 4.

[0053] The docking station 6 has been described in general terms above to
place it in a suitable context. It's mechanical and electrical features
will now be described in more detail with reference to FIGS. 4 to 12.

[0054] The docking station 6 comprises two major components: a base
portion 60 and a back portion 62 that is pivotable with respect to the
base portion 60. The docking station 6 is positionable by a user in a
room and, typically, the user will choose to position the base portion 60
so that a rear edge of it is adjacent a wall, as is shown in FIG. 1. The
back portion 62 is generally rectangular and substantially flat in this
embodiment, although it will be appreciated that this is not essential
and the back portion 62 may be shaped differently as long as it is able
to fold against the base portion 60.

[0055] As can be seen by comparing FIGS. 4 and 5, the docking station 6 is
foldable in the sense that the back portion 62 is hinged with respect to
the base portion 60. In this embodiment, the back portion 62 and the base
portion 60 are relatively flat in form and this allows the two components
to be pivoted between an unfolded or `deployed` position (FIG. 4) and a
folded or `stowed` position (FIG. 5) in which the back portion 62 pivots
through approximately 90 degrees so as to lie against the base portion
60, in which position they are substantially parallel. In the stowed
position, therefore, the docking station 6 is has a low profile from the
side and can readily be stored away if necessary, and it is also is a
very efficient shape for transportation since it takes up minimal
packaging volume.

[0056] In more detail, the base portion 60 includes an elongate rear
portion 64 and a platform 70 that extends forwardly from the rear portion
64. The base portion 60 therefore takes the general form of a `T` with
the lateral bar of the T being the elongate rear portion 64 and the trunk
of the `T` being the forward platform 70.

[0057] The back portion 62 of the docking station is hinged to and is
removable from the elongate rear portion 70 which thereby serves as a
pivot region of the base portion 60. A long edge 72 of the back portion
62 includes first and second sleeves 74 that are spaced apart one at each
end of the long edge 72. The sleeves are C-shaped in cross section such
that a pair of opposed leading edges 76, 78 define a channel or slot 80
that faces away from the long edge 72 of the back portion 62. The channel
80 provides the sleeves 76, 78 with a degree of radial resilience so that
the sleeve diameter can expand slightly in order to be mounted to the
base portion 60 in a snap-fit action. The sleeves 74 thereby serve as a
mounting interface that mates with a complementary interface provided by
the elongate rear portion 64.

[0058] As shown in FIG. 7, the elongate rear portion 64 of the base
portion 60 includes first and second pivot axles 82 that extend away from
either side of the platform 70 and are aligned on a axis X. The pivot
axles 82 are generally cylindrical and are dimensioned so as to receive
the sleeves 76, 78 of the back portion 92 in a sliding fit. As the
sleeves 74, 76 define a sliding fit around the pivot axles 82, this
allows the back portion 62 to pivot with respect to the base portion 60.

[0059] In order that the back portion 62 is able to remain in the deployed
condition once it is set, the pivot axles 82 includes detent means 84
that cooperate with the sleeves 76, 78. At this point it should be noted
that the detent means 84 are identical on each of the pivot axles 82 so
only one of them will be described in detail here for brevity, as
illustrated in FIGS. 7, 8a-c and 9a-c.

[0060] The detent means 84 comprises longitudinal groove formations
provided on inboard and outboard regions of the pivot axle 82. Note that
for the purpose of this description, the inboard region is the section of
the pivot axle 82 nearest the platform indicated generally as 86 and the
outboard region is the section of the pivot axle 82 adjacent the inboard
section but remote from the platform 70 indicated generally as 88. The
groove formations in this embodiment are elongated and substantially
straight although it should be appreciated that this is not essential.

[0061] In overview, the inboard region 86 includes first and second
grooves labeled as 90 and 92 respectively and the outboard region 88
includes third and fourth grooves labeled 94 and 96, respectively. The
outboard region 88 also includes a transition surface 98 that extends
between the third and fourth grooves 94, 96. The grooves 90-96 complement
engagement ribs provided on inboard and outboard regions 100, 102 of the
sleeves 74 which are configured to mate with the grooves, as will be
explained. The ribs can be seen in FIG. 6 such that a first rib 100 is
provided on an inboard region 102 of one of the leading edges 78 of the
sleeve 74 and a second rib 104 is provided on an outboard region 106 of
the sleeve 74 on the opposed leading edge 76.

[0062] FIGS. 8a to 8c illustrate the engagement between the sleeve 74 and
the pivot axles 82 when the back portion 62 is in the stowed condition.
With specific reference to FIG. 8b, which shows a section through the
outboard regions 88, 106 of the pivot axle 82 and sleeve 74, the second
rib 104 is seated in the fourth groove 96. Similarly, with reference to
FIG. 8c, which shows a section through the inboard regions 86, 102 of the
pivot axle 82 and the sleeve 84, the first rib 100 is seated in the
second groove 92. The second and fourth grooves 94, 96 therefore define a
first set of grooves.

[0063] By virtue of the ribs 100, 104 being located in the second and
fourth grooves 94, 96 the back portion 62 and the base portion 60 are
held in a folded position quite firmly which guards against inadvertent
deployment of the docking station. However, due to the radial resilience
of the sleeve 72, the ribs 100, 104 are able to be released or `bump out`
of the grooves once a sufficient torque is applied to the sleeve 72 via a
force applied to the back portion 62. Such an arrangement provides a
positive feel to the stowed position. The skilled person would appreciate
that the amount of force required is largely subjective although it would
not be desirable to configure the groove formations so that too high a
force was required to deploy the back portion 62. In practice, it has
been found that a force of approximately 5 N (Newtons)+/-2 N applied to
the upper edge of the back portion 62 provides a suitable amount of
`feel`.

[0064] Once the ribs 100, 104 have been released from the grooves 96, 92,
the sleeve 72 is permitted to slide freely around the outer periphery of
the pivot axle 82 toward a second set of grooves (the first groove 90 and
the third groove 94) in which position the docking station 6 is in the
deployed condition.

[0065] In this respect, FIGS. 9a to 9c illustrate the engagement between
the sleeve 74 and the pivot axles 82 when the docking station is in the
deployed condition. With specific reference to FIG. 9b, which shows a
section through the outboard region 88 of the pivot axle 82 and outboard
region 106 of the sleeve 74, the second rib 104 is seated in the third
groove 94. Similarly, with reference to FIG. 9c, the first rib 100 is
seated in the first groove 90.

[0066] By virtue of the ribs 100, 104 being located in the first and third
grooves 90, 94, the back portion 62 and base portion 60 are held firmly
in the deployed condition. However, in the same way that a predetermined
force is required to free the ribs 100, 104 from the first set of grooves
when in the stowed position, a predetermined force is also required to
free the ribs 100, 104 from the second set of grooves in the deployed
position. Such an arrangement provides a positive feel to the deployed
position of the docking station and confirms to the user that it is in
the correct position.

[0067] The transition region 98 provided on the outboard region 88 of the
pivot axle 82 provides the user with a sense of `feel` when transitioning
the docking station 6 between stowed and deployed conditions. The
transition region 98 can be seen in FIG. 7, and also in cross section in
FIGS. 8b and 9b. The transition region 98 comprises a cam surface which
extends between the fourth groove 96 and the third groove 94. As can be
seen in FIGS. 8b and 9b the cam surface of the transition region 98
increases in diameter from the fourth groove 96 to the third groove 94
and terminates at the third groove 94. The effect of this is that the
user will feel a gradual increase of resistance as the docking station 6
is moved into its deployed condition and the docking station will `click`
into place as the deployed condition is reached as the ribs 104 locate
into the third grooves 94.

[0068] The folding action of the docking station has been described above
and attention will now turn to the electrical system of the docking
station, with further reference to FIGS. 10, 11a, b and 12a, b.

[0069] As has been mentioned above, the primary function of the docking
station 6 is to provide a means by which the robot 4 can recharge its
on-board battery pack 56. In order to achieve this function the docking
station 6 itself should be connectable to a source of power and should
have a means to transfer charge to the robot 4 which, in this embodiment,
is provided by the electrical contact means 8 as mentioned above. In this
context, the base portion 60 houses an electrical charging system 120 of
the docking station 6. In overview, the electrical charging system 120
comprises the electrical contact means 8, a power supply electronic board
124 and associated switching mechanism 125 and a power supply loom 126.

[0070] Power is supplied to the electrical charging system 120 by way of
first and second power input sockets 128 provided on opposite side
portions of the base portion 60. More specifically, the first and second
power input sockets 128 are housed in the elongate rear portion 64 of the
base portion 60. A tubular housing 129 of high strength acrylonitrile
butadiene styrene (ABS) extends 129 through the pivot axles and provides
a strengthened spine for the elongate rear portion 64. A polymeric
material is preferred for efficiency of manufacture but it should be
appreciated that other materials such as a tubular metallic material
would also be acceptable.

[0071] The outer end of the pivot axles 82 are open so as to permit a
power supply plug or jack 127 associated with the cable 12 to be inserted
into either one of the sockets 128. Such an arrangement allows the
positioning of the docking station 6 to be flexible. Since any given room
in a dwelling, for example, only has a limited number of wall-mounted
mains plug sockets, the user may be restricted to locating the docking
station on a particular side of the power input sockets. If the docking
station has only a single power input socket, the positioning of the
docking station may mean that the power input socket faces away from the
mains plug socket which would require an inconvenient routing of the
mains power cable. Having a power input socket provided on both sides of
the docking station avoids this.

[0072] In this embodiment, the power input sockets 128 are located on
opposite sides of the docking station and are aligned along the axis X of
the elongate rear portion 64. However, it should be appreciated that this
is not essential and that the power input sockets 128 need not be axially
aligned. The important factor is that a user is given more than one
location to provide power to the docking station which makes the location
of the docking station in a room more flexible.

[0073] The power supply loom 126 leads from the power input sockets 128 to
the electronic board 124. Although not show explicitly in the Figures,
the electronics board 124 contains all of the necessary circuitry to
supply a suitable voltage and current to the robot 4 via the electrical
contact means 8 when the robot 4 reaches a docked position.

[0074] The electrical contact means 8 comprises first and second
electrically conductive power supply contacts 130a, 130b which are
resiliently mounted to a lower housing part 132 of the base portion 60.
In this embodiment, each of the supply contacts 130a, 130b are mounted on
a pair of coil springs although it should be appreciated that other means
of resiliently mounting the contacts are envisaged. For example, the
contacts 130a, 130b could be mounted on leaf springs, resilient rubber
buffers, fluid-filled cushions to name a few non-limiting examples. By
virtue of the resilient mounts, the contacts 130a, 130b are urged
upwardly away from the lower housing part 132 so that upper surfaces of
the contacts protrude through openings 134 provided in the upper surface
of the base portion 60. A force applied to the contacts 130a, 130b causes
them to recede into the openings but this ensures that a positive
electrical contact can be established between the robot contacts 28, 30
and the docking station contacts 130a, 130b. The contacts 130a, 130b are
electrically conductive and in this embodiment are formed from pressed
brass alloy having a nickel coating for durability purposes. However,
other electrically conductive materials, metallic or otherwise, would be
apparent to the skilled person.

[0075] In order to trigger the supply of power to the contacts 130a, 130b,
the docking station 6 includes an activating mechanism 140 which is
operable to move between on and off positions. The activating mechanism
140 therefore serves as a safety feature since the contacts 130a, b are
not `live` until the mechanism has been activated, as will now be
described.

[0076] As shown in FIG. 10, the activating mechanism comprises a
mechanically driven actuator 142 that is paddle-like in form. The
actuator comprises tubular body 144 that is journalled in the gap between
the pivot axles 82 and an operating lever 146 that extends away at an
oblique angle from the body 144. Since the body 144 is journalled to the
base portion 60 the lever 146 is able to move angular about the axis of
the pivot axles 82 between first and second positions. The two operating
positions of the actuator 142 are shown in FIGS. 11b and 12b. In FIG. 11b
the actuator 142 is in an `power off` position such that the contacts
130a, 130b are not supplied with power and in FIG. 12b, the actuator 142
has been moved angularly to that it abuts the back portion 62 and is in
an `power on` position such that power is supplied to the contacts 130a,
130b. It should be noted that the lever 146 will be pushed into the `on`
position when the robot has manoeuvred into an acceptable docking
position.

[0077] The actuator 142 cooperates with the power electronics board 124 in
order to control the flow of power to the contacts 130a, 130b. It should
be appreciated here that the circuit board 124 is populated with
components for illustrative purposes and they are not intended to be a
precise and limiting representation. Suffice to say that the power
electronics board 124 has the necessary components to relay the input
power supplied at the input sockets 128 to a suitable output voltage at
the electrical contacts 130a, 130b.

[0078] To this end, one option is for the power supply 12 attached to the
electrical mains outlet 10 in the room to convert the mains voltage
available at the outlet (UK: 240 VAC at approximately 13 A) to a suitable
low value DC voltage for the docking station 6, for example between 15
and 20 VDC. The functionality of the electronics board 124 would
therefore chiefly involve turning the power supply to the contact means 8
on and off as required which would simplify the electrical configuration
of the electronics board 124 and this is currently considered to be
preferable. Alternatively, the power supply 12 attached to the wall
outlet 10 may be configured simply to connect the electronics board 124
directly to the mains outlet voltage so that the electronics board 124
would be required to convert the high value AC voltage to a suitable DC
voltage for supply to the contact means 8. However, such functionality
would require suitable power transformer and rectification circuitry
thereby adding to the space requirement of the electronics board 124 and
also would increase the power dissipation, which may not be desirable.

[0079] It should be noted that although not shown in the Figures, means
may be provided in the power input sockets 128 and the associated power
supply loom 126 to ensure that only one of the power supply sockets 128
can supply power to the electronics board 124 in the unlikely event of a
user attempting to plug a power jack 127 into both power input sockets
128. In this embodiment, each of the power input sockets 128 includes a
switch that activates to disable the opposing power input socket 128 in
circumstances when a power jack 127 is inserted into the socket 128. The
power input jacks 127 and the associated sockets 128 may be suitable `off
the shelf` parts--for example the power input jacks 127 may be supplied
by Shen Miong Electron (Dong Guan) Co., Ltd. under part number 865-818
and the power input sockets 128 may be supplied by Technik Industrial
Co., Ltd under part number TDC-091-PA662D-TS.

[0080] The activating mechanism further includes a tooth 150 located on
the body 144 of the actuator 142 which acts against a slider 152 which,
in turn, is engageable with a trigger switch 154 in the form of a
miniature snap-action switch located on the power electronics board 124.
The slider 152 includes an enlarged mid-section 152a that triggers and
releases the microswitch 154 as the slider 152 is moved linearly to and
fro within a channel 156 defined by the base position 60. The far end of
the channel 156 defines an end stop 158 which serves as an abutment
surface for a spring (not shown) which acts on the slider 152 to bias it
in a position away from the microswitch 154.

[0081] In FIG. 11a, the activating mechanism 140 is in the `off` position
and it can be seen that the tooth 150 is in an angular position such that
the slider 152 is retracted relative to the microswitch 154 so that the
microswitch is not triggered. In this position, therefore, the contacts
130a, 130b are not electrically active. The position in FIG. 11a should
be compared with FIG. 12a in which the tooth has moved angularly with
movement of the lever 146 so as to push the slider 152 up the channel 156
thereby triggering the microswitch 154 so that the contacts 130a, 130b
become electrically active.

[0082] In order that the activating mechanism returns reliably to its
inactive state, a biasing means is provided which in this embodiment is
in the form of a helical torsion spring 160 that is mounted against an
end of the actuator body 144 and is braced against the body 144 and a
retention point 162 on the housing 160.

[0083] The above discussion explains the manner in which the electrical
contacts 130a, 130b are switched between inactive and active states
through the robot 4 actuating the lever 146, which therefore serves as a
safety interlock to ensure that a user cannot injure themselves through
normal user of the robot. In order to actuate the lever 146, the robot 4
must be in an acceptable docked position, and the configuration of the
contacts facilitates this, as the following discussion will make clear.

[0084] As has been explained above, the elongate contacts 130a, 130b have
a length that extends in a direction transverse to the longitudinal axis
of the base portion 60. In this embodiment, the length of each contact
130a, 130b is 60 mm and the width is approximately 5 mm, although it is
to be understood that these dimensions are exemplary. It is important,
however that at least one of the contacts, preferably the second contact
130b is elongate, that is to say longer than it is wide, in order to
allow for lateral and angular misalignment between the robot and the
docking station as will now be described. The significance of this
technical aspect will now be explained with respect to FIGS. 13 and 14,
FIGS. 15a,15b, and FIGS. 16a,16b. Here, the longitudinal axis of the
robot 4 is indicated as L, the longitudinal axis of the base portion 60
is indicated as LL and the contacts 130a, 130b are aligned in parallel
with a further axis T that is substantially perpendicular to the
longitudinal axis LL, and parallel to the axis X of the elongate rear
portion 64.

[0085] FIG. 13 shows the robot 4 docked with the docking station in a
`nominal` docking position. As can be seen the charging contacts 28, 30
of the robot 4 (and, therefore, also the longitudinal axis L of the
robot) are aligned with the longitudinal axis LL of the docking station
and therefore engage the electrical contacts 130a, 130b substantially at
their midpoints. From another perspective, FIG. 14 show the spatial
relationship between the robot 4 and the docking station 6 from the side,
where it can be seen that the contacts 28, 30 on the robot 4 are touching
the contacts 130a, 130b on the docking station 6 when the robot 4 is in a
docked position.

[0086] The nominal docking position is an idealized position at which the
robot 4 is able to dock with the docking station 6. In practice, the
navigation system of the robot 4 may not be able to return it precisely
to the nominal position. However, the transverse configuration of the
electrical contacts 28, 30 of the robot 4 in relation to the orientation
of the electrical contacts 130a, 130b of the docking station is such that
a significant degree of misalignment between the robot 4 and the docking
station 6 is permitted whilst still achieving a successful electrical
contact between them.

[0087] FIGS. 15a and 15b show two extreme laterally misaligned docking
positions of the robot. In FIG. 15a, the robot 4 is positioned at a
maximum left position and, as illustrated, the longitudinal axis L of the
robot 4 is spaced to the left of the longitudinal axis LL of the docking
station 6 by a distance X1. In contrast, FIG. 15b shows the robot 4
positioned at a maximum right position and, as illustrated, the
longitudinal axis L of the robot 4 is spaced to the right of the
longitudinal axis LL of the docking station 6 by a distance X2. It
will be appreciated therefore, that the robot is able to dock with the
docking station with a misalignment of up to X1+X2 whilst still
achieving a successful electrical contact. A suitable distance for
X1 and X2 is 30 mm although it should be appreciated that this
is only exemplary and the contacts may be any suitable length.

[0088] As well as permitting a significant degree of lateral misalignment
between the robot and the docking station away from the nominal docking
position, the complementary configuration of the electrical contacts 28,
30 on the robot and the contacts 130a, 130b on the docking station 6 also
permits significant angular alignment, as will now be described with
reference to FIGS. 16a and 16b.

[0089] Comparing the position of the docking position of the robot 4 in
FIG. 16a with the nominal docking position of the robot 4 illustrated in
FIG. 13, it can be seen that the transverse orientation between the
contacts 28, 30 on the robot 4 and the contacts 130a, 130b on the docking
station 6 permits a significant angular misalignment in the anticlockwise
direction of at least θ1 degrees. Conversely, FIG. 16b shows
that the traverse configuration of contacts will allow an angular
misalignment between the robot 4 and the docking station 6 in the
clockwise direction of at least θ2 degrees. It will therefore
be appreciated that that the robot 4 is still able to dock electrically
with the docking station 6 through a range of angular positions away from
the nominal position as illustrated in FIG. 13. With the present
embodiment, it is envisaged that the transverse configuration of the
contacts will permit a total angular range of misalignment of between 10
and 30 degrees.

[0090] The benefit of this is that the navigation system does not have to
function with pinpoint accuracy during the process of docking the robot 4
with the docking station 6. As is seen in the prior art, it is common for
docking station to include directional beaming systems, using ultrasonics
or infrared transmitters, that guide the robot towards a precise docking
position on the docking station. Although such systems have the potential
of being highly accurate, they add to the complexity and cost of the
docking station and the robot. In contrast, in the robotic system of the
invention, the navigation system is only required to maneuver the robot
towards the docking station within a significant zone of lateral and
angular misalignment and it will still achieve a successful electrical
engagement with the docking station so that its internal batteries can be
charged.

[0091] Some alternatives to the specific embodiments described above have
already been explained. However, the skilled person will understand that
other variations and modifications may be made to the specific
embodiments without departing from the scope of the invention as defined
by the claims.

[0092] In the specific embodiment described above, the back portion 62 is
hinged to the base portion 60 by way of the two sleeves 74 that fit onto
the associated pivot axles 82. Such an arrangement is technically
advantageous since it does not require many parts to form the hinge and
it is elegantly simple. Moreover, due to the snap-fit action of the
components a user may disassemble and re-assemble the back portion 62 as
desired. However, although such a hinged structure is preferred, the
skilled person would appreciated that other hinge mechanisms would also
result in the folding relationship between the back portion 62 and the
base portion 60. For example the back portion 62 could be secured to a
suitable bracket or brackets being pivotably attached to the base portion
60.

[0093] The robot of the invention has been described as using a
rechargeable power source in the form of an internal battery pack. Of
course, batteries are the most convenient form of rechargeable power
source in such a robotic application but this does not rule out other
forms of power sources being used such as large capacitive units for
example.

[0094] Although the electrical contacts 130a, 130b on the base portion 60
have been described as elongate, linear, and equal in length, other forms
may be suitable. For example, instead of being linear, the contacts 130a,
130b may be curved or arcuate. Some examples of this are shown in FIGS.
17a, b and c. In FIG. 17a, both of the first and second contacts 130a,
130b are elongate but are curved. In this case each of the contacts 130a,
130b have substantially the same radius of curvature and subtend
substantially the same degree of arc. Such a configuration may
accommodate a wider range of angular misalignment between the robot 2 and
the docking station 6 particularly when the robot is in a nominally
central position laterally. In FIG. 17b, both of the contacts 130a, 130b
are curved with substantially the same radius of curvature, but the first
contact 130a is shorter than the second contact 130b such that it
subtends a smaller degree of arc. An extreme example is illustrated in
FIG. 17c in which the first contact 130a is not elongate and is in fact
substantially circular whilst the second contact 130b is elongate and
curved as in the previous examples.

[0095] Turning to the electrical contacts 28, 30 provided on the robot 2,
although they have been described above as being aligned on a
longitudinal axis L of the robot, it should be appreciated that the
contacts 28, 30 may also be linearly aligned with each other but not
aligned along the longitudinal axis L of the robot 2 but offset
therefrom. Furthermore, each of the contacts 28, 30 may be offset from
one another should this be desirable due to space constraints, and there
may be more than two robot contacts 28, 30. For example a further
electrical contact could be provided in order to serve to pick up an
auxiliary electrical signal provided by a further electrical contact
provided on the docking station, or the further electrical contact could
be an electrical earth.

[0096] The activating mechanism 140 discussed above takes the form of a
lever 146 that is pivotably mounted to the rear portion 64 of the docking
station 6. Such a configuration provides a space-efficient solution to
the problem of interlocking the supply of charging energy to the docking
station contacts 130a 130b to the correct positioning of the robot 2 on
the docking station. However, as an alternative to a pivoting lever, a
linear travelling push rod (not shown) for example could be used to
achieve a similar power interlocking function.

[0097] Although the above discussion has focused on a mobile robot having
electrical contacts 28, 30 provided on its underside for cooperating with
the electrical contact means 8 provided on the upper surface of the base
portion 60 of the docking station, it should be appreciated that an
equivalent affect would, in theory, be achievable if the electrical
contacts 28, 30 of the robot were provided on its upper surface whilst
the contact means of the docking station were provided on a surface that
extended over the top of the mobile robot in order to establish
communication with the robot's contacts 28, 30.

Patent applications by DYSON TECHNOLOGY LIMITED

Patent applications in class CELL OR BATTERY CHARGER STRUCTURE

Patent applications in all subclasses CELL OR BATTERY CHARGER STRUCTURE